JP3483591B2 - Exhaust device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust device for exhausting gas in a specific space through a relief valve. 2. Description of the Related Art For example, a semiconductor wafer (hereinafter, "wafer")
For example, when various processes such as an ion implantation process and an etching process are performed, these processes are performed in an airtightly configured processing chamber in an appropriate processing gas such as an ion implantation process. , A mixed gas of PH ₃ and H _2, and in the case of an etching process, a CHF ₃ gas or the like are introduced, and the process is performed under a predetermined reduced pressure atmosphere. [0003] The processing chamber is evacuated by an exhaust means such as a vacuum pump in order to reduce the pressure in the processing chamber to a predetermined reduced pressure value. The exhaust gas is a highly flammable gas or a toxic gas as described above. Therefore, these cannot be exhausted to the atmosphere as they are. Before diluting into the atmosphere, an appropriate diluent gas such as Ar gas or N ₂ is mixed and diluted, and then exhausted. I have. This will be described in detail with reference to, for example, an exhaust device attached to an ion implantation apparatus with reference to FIG. 8. Processing gas exhausted from a processing chamber is passed through a gate valve (not shown). Are stored in the cryopump 51. A housing 53 is provided in an exhaust port 52 of the cryopump 51, and a relief valve 58 including a locking body 54, a spring 55, a valve body 56, a flange 57, and the like is provided in the housing 53. I have. The cryopump 51 depressurizes the inside of the processing chamber by causing a cryogenic panel (not shown) provided therein to adsorb the processing gas in the processing chamber.
Further, the inside of the cryopump 51 is always 10 ⁻⁷ Torr.
Hereinafter, a high vacuum of, for example, 10 ⁻⁸ to 10 ⁻⁹ Torr is maintained. After a certain period of operation, that is, when the amount of gas stored in the cryopump 51 approaches the limit, an operation of "regeneration" of the cryopump 51 is performed. This regeneration is performed by simultaneously stopping the operation of the cryopump 51 and simultaneously introducing, for example, N ₂ gas into the cryopump 51.
This is performed by raising the temperature of the cryogenic panel to release the adsorbed processing gas. When the gas thus released and the introduced N ₂ gas are mixed, the inside of the cryopump 51 eventually becomes atmospheric pressure, and the pressure further increases to reach the set pressure of the relief valve 58. The mixed gas of the released gas and the N ₂ gas is released from the relief valve 58 into the housing 53. On the other hand, a diluent gas supplied by a diluent gas supply pipe 59 for further diluting the mixed gas discharged as described above is supplied to the inside of the housing 53 through a supply port 60 provided in a wall of the housing 53. The processing gas exhausted into the housing 53 through the relief valve 58 is mixed with the processing gas in the mixing chamber 61 to dilute the processing gas, and then the exhaust gas is provided in the wall of the housing 53. The air is exhausted to the outside through an exhaust hose 63 connected to the exhaust port 62. When the internal pressure of the cryopump 51 rises to a predetermined value during regeneration of the cryopump 51 as described above, the valve element 56 of the relief valve 58 is opened, and the processing gas (mixed gas) in the cryopump 51 is supplied to the housing. 5
The gas is discharged into a mixing chamber 61 in the mixing chamber 3, where it is mixed with a diluent gas supplied from a supply port 60, further diluted, and exhausted from an exhaust port 62 through an exhaust hose 63. [0007] However, according to the conventional exhaust device having the above-described structure, the following problems occur. That is, since the diluent gas supplied by the diluent gas supply pipe 59 is supplied from the supply port 60 provided in the wall of the housing 53, the pressure in the mixing chamber 61 in the housing 53 is reduced by the supply of the diluent gas. It becomes large corresponding to the flow rate. Therefore, when the supply flow rate of the dilution gas is increased, the pressure in the mixing chamber 61 is also increased, and the valve body 56 of the relief valve 58 is connected to the exhaust port 52.
It pushes to the side. As a result, even if the pressure in the cryopump 51 reaches a desired value, the valve body 56 does not open, and the amount of processing gas exhausted by a single opening decreases. There is a possibility that a failure occurs in each device of the exhaust system including the pump 51, and that the processing device itself does not function properly. SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides an exhaust system of this type in which a relief valve always functions normally irrespective of the supply amount of a diluent gas, thereby solving the above-mentioned problems. It is intended. [0010] In order to achieve the above object, according to the present invention, when exhausting gas in a specific space through a relief valve, the relief valve is provided in a housing, and further, the relief valve is provided in the housing. In a device configured to introduce a dilution gas to dilute the gas and exhaust the gas through an exhaust port provided in the housing, an introduction port for introducing the dilution gas into the housing is guided to the inside of the housing. In addition, the present invention provides an exhaust device, wherein the inlet is directed toward the exhaust port. The introduction port for introducing the dilution gas is guided to the inside of the housing, and the introduction port is directed to the exhaust port. The gas is blown out to the exhaust port side as if the inlet were the outlet of the nozzle. Accordingly, the pressure in the housing does not increase and the valve body of the relief valve is not pressed toward the closing side, and the relief valve reliably performs the intended opening operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an exhaust system of an ion implanter will be described below with reference to the drawings. FIG. The injection device 1 includes a terminal module 2 and an end station module 3. The terminal module 2 is provided with an ion source 4 for generating ions from a predetermined source gas, a mass spectrometric electromagnet 5, and an accelerating tube 6 for accelerating the ions. The ions thus selected are selected by the mass spectrometric electromagnet 5, accelerated by the accelerating tube 6, become an ion beam having an energy of, for example, 2 to 200 KeV, and irradiated into the main chamber 7 of the end station module 3. It has become so. 1 and 2 in the main chamber 7.
As shown in FIG. 1, a disk-shaped disk 8 configured to hold a large number of wafers W to be processed on one side thereof is provided. The disk 8 is configured so that it can be set up vertically from a horizontal state, as shown by a reciprocating rotation arrow in FIG. 2, and the disk 8 is placed in a vertical state shown by a dashed line in FIG. Is rotated to irradiate the ion beam to a large number of wafers W held as described above. The inside of the main chamber 7 is roughed by a so-called roughing pump 10 such as a rotary pump or a dry pump through an exhaust port 9 as shown in FIG. The pressure is reduced by a cryopump 13 provided through the vacuum pump, and a high vacuum degree of, for example, 10 ⁻⁷ Torr or less can be set. Further, in the main chamber 7, FIG.
Three load lock chambers 14, 15, as shown in FIG.
16 are provided in parallel. Each of the load lock chambers 14, 15, 16 has the same configuration. The load lock chamber 16 located at one end will be described with reference to FIG. The cassette chamber 17 comprises a bell jar 18 which can be vertically moved by an elevating device (not shown). In the upper part of the cassette chamber 17, a roughing pump 10 and a cryopump 18 provided separately are provided.
The roughing pump 10 and the cryopump 18 evacuate the inside of the bell jar 18 to a predetermined high degree of vacuum, for example, 10 mm.
It is configured such that it can be set to a reduced pressure atmosphere of ^-7 Torr or less. In the cassette chamber 17, a table 2 which can be moved up and down by an appropriate elevating device (not shown).
0, and a table 20a is further provided on the table 20. A storage cassette 21 for storing, for example, 25 wafers W is configured to be mounted on the table 20a. ing. Then, as shown in FIG. 2, the table 20 is raised so that the peripheral edge of the upper surface thereof is positioned in the cassette chamber 1.
By tightly contacting the inner peripheral edge of the opening of the cassette 7, the cassette chamber 17 and the space inside the bell jar 18 are airtightly partitioned by the table 20, and the bell jar 18 is configured to have a load lock function. The main chamber 7 opposed to the load lock chambers 14, 15, 16 constructed as described above.
Inside, between the aforementioned disk 8 and the storage cassette 21,
A transfer device T for transferring the wafer W is provided. The present embodiment is applied to the exhaust system of the main chamber 7 of the ion implantation apparatus 1 having the above configuration. That is, the main chamber 7 and the load lock chamber 1
A gas containing a processing gas or the like exhausted from 4, 15, 16 (hereinafter, simply referred to as a “processing gas”) is adsorbed and stored in a cryogenic panel (not shown) in the cryopump 13, As a result, the main chamber 7 and the load lock chambers 14, 15, 16 are maintained in the above-described predetermined reduced-pressure atmosphere. The exhaust port 23 of the cryopump 13
Is connected to one end of a substantially cylindrical housing 24 as shown in FIGS. 3, 4 and 5, and the other end of the housing 24 forming the exhaust port 25 is connected to the other end. Flexible exhaust hose 26 leading to a centralized exhaust device (not shown) for exhausting to the atmosphere together with the exhaust from the exhaust system of FIG.
Is connected. A relief valve 27 is provided in the internal space of the housing 24. The relief valve 27 includes a plurality of through holes 22 serving as flow paths, and a flange 28 fixed to an inner wall of the housing 24 so as to partition an internal space of the housing 24 at right angles to an axial direction.
A support shaft 29 inserted into the center hole of the support shaft 29, a disc-shaped locking member 30 provided on the exhaust port 23 side of the support shaft 29, and the through hole 22 provided on the exhaust port 25 side of the support shaft 29. The valve body 31 to be closed is constituted by a spring 32 provided between the locking body 30 and the flange 28, and an O-ring for ensuring airtightness is provided on the flange 28 side end surface of the valve body 31. Is provided. The space between the flange 28 and the exhaust port 25 in the housing 24 is a mixing chamber 34.
It is constituted as. On the outer peripheral wall of the housing 24,
The joint member 36 of the dilution gas supply pipe 35 is connected.
As shown in FIG. 2, the dilution gas supply pipe 35 communicates with a gas cylinder 39 via a valve 37 and a flow control valve 38 for controlling a flow rate. ₂ gas is filled. An introduction pipe 40 is connected to the joint member 36. The introduction pipe 40 is bent at a substantially right angle on the way, and is formed into a discharge port 41 at the tip end serving as an introduction port.
Are directed to the exhaust port 25. This embodiment is configured as described above.
Next, the evacuation operation will be described. In the normal state, that is, when the processing gas is being accumulated in the cryopump 13, the inside of the cryopump 13 is 10 ⁻⁷ Torr as described above.
Since the pressure is less than r, the pressure difference
The valve element 31 of the relief valve 27 is pressed toward the flange 28, the through hole 22 is closed, and the relief valve 27 is closed. When the cryopump 13 is regenerated, for example, N ₂ gas is introduced into the cryopump 13 by a separate dilution gas supply device (not shown), so that the pressure in the cryopump 13 increases and exceeds the atmospheric pressure. A predetermined opening pressure of the relief valve 27, for example, 0.3 kgf / c
When the pressure reaches m ² , the valve 31 is pressed toward the mixing chamber 34 by the pressure in the cryopump 13 through the through hole 22. As a result, the close contact state of the valve body 31 with the flange 28 is released, the relief valve 27 is opened, and the cryopump 1
The processing gas in 3 together with the above-mentioned N ₂ gas and the flange 28
Is discharged into the mixing chamber 34 from the through-hole 22 of the nozzle. At this time, before the processing gas previously mixed with the N ₂ gas reaches the predetermined pressure value, the valve 37 is opened and the N ₂ gas from the gas cylinder 39 is supplied to the dilution gas supply pipe 35 and the introduction pipe. Even if the gas is introduced into the housing 24 through 40, the discharge port 41 is directed toward the exhaust port 25, so that the pressure in the housing 24 increases due to the introduction of N ₂ gas into the housing 24. There is no. Accordingly, the relief valve 27 is opened immediately when the intended pressure value is reached, and the released processing gas is further diluted by mixing with N ₂ gas and exhausted from the exhaust hose 26. It is. Further, as described above, since the discharge port 41 of the introduction pipe 40 is directed toward the exhaust port 25, the flow rate of the N ₂ gas is increased by, for example, the flow rate control valve 38 to increase the degree of dilution. However, the pressure in the housing 24 does not rise, and when the pressure of the processing gas in the cryopump 13 reaches a predetermined pressure value, the relief valve 27 is reliably opened. As described above, when the processing gas discharge operation (regeneration operation) in the cryopump 13 is completed after a predetermined time, for example, about one hour, the dilution gas supply device supplies the processing gas into the cryopump 13. When the supply of the N ₂ gas is stopped, the relief valve 27 is closed. Then, the roughing pump 10 is operated to reduce the pressure inside the cryopump 13 to, for example, 10 ⁻² Torr. Thereafter, the cryopump 13 itself is operated, and the cryogenic panel in the cryopump 13 is cooled again. At the time when a predetermined high vacuum degree, for example, 10 ^-7 Torr or less,
The gate valve 12 is opened and the normal operation starts. As described above, the relief valve 27 always functions normally irrespective of the introduction amount of the N ₂ gas as the diluent gas. And the processing of the processing apparatus to which the exhaust system is applied can be smoothly carried out as designed. Although the introduction tube 40 in the above embodiment is a bent tube that has been bent in the middle as described above,
Instead of this, for example, a straight pipe-shaped introduction pipe 45 as shown in FIG. 6 can be used. That is, the straight pipe-shaped inlet pipe 45 has a structure in which the tip is closed, and as shown in FIG. 46 is provided. Even with the introduction pipe 45 having such a straight pipe shape, the same effect as that of the introduction pipe 40 of the above embodiment can be obtained, and the relief valve 27 is always operated regardless of the amount of N ₂ gas introduced. It works properly. As can be seen from the above embodiment, the connecting member 36 is connected to the dilution gas supply pipe in the existing exhaust system.
And the present invention can be implemented simply by connecting the introduction pipes 40 and 45 having the simple configuration as described above, so that the present invention can be applied at a low cost to an existing apparatus that is already operating. It is. Although the above embodiment is an example in which the present invention is applied to an exhaust system of an ion implantation apparatus, the present invention is not limited to this. For example, various apparatuses such as an etching apparatus, an ashing apparatus, a CVD apparatus, and a sputtering apparatus may be used. The present invention can be applied to an exhaust system of a processing apparatus. According to the present invention, the relief valve is always opened when the pressure reaches a predetermined value, irrespective of the amount of diluent gas introduced. Therefore, even when a large amount of dilution gas is required, the gas in the specific space can be reliably diluted and exhausted without hindering the function of the relief valve.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory plan view of an ion implantation apparatus in which an embodiment of the present invention is applied to an exhaust system. FIG. 2 is an explanatory cross-sectional view of an end station module of an ion implantation apparatus in which an embodiment of the present invention is applied to an exhaust system. FIG. 3 is a perspective view showing an outer shape of the embodiment of the present invention. FIG. 4 is a perspective view showing an internal configuration of the embodiment of the present invention. FIG. 5 is a partial sectional front view of the embodiment of the present invention. FIG. 6 is a sectional view showing another example of the introduction pipe used in the embodiment. FIG. 7 is a partial cross-sectional front view of another embodiment of the present invention. FIG. 8 is a partial cross-sectional front view of an exhaust device according to the related art. [Description of Signs] 13 Cryopump 22 Through-hole 23 Exhaust port 24 Housing 25 Exhaust port 26 Exhaust hose 27 Relief valve 31 Valve element 34 Mixing chamber 35 Diluent gas supply pipe 40 Inlet pipe 41 Discharge port

Continuation of the front page (56) References JP-A-4-128575 (JP, A) JP-A-5-33766 (JP, A) JP-A-61-294176 (JP, A) JP-A-6-129352 (JP) , A) JP-A-5-99139 (JP, A) JP-A-4-353273 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04B 37/08 H01J 37/18 H01J 37/317 H01L 21/3065

Claims (1)

(57) [Claim 1] When exhausting a gas in a specific space through a relief valve, the relief valve is provided in a housing, and a dilution gas is introduced into the housing to remove the gas. In an apparatus configured to be diluted and exhausted from an exhaust port provided in the housing, an introduction port for introducing the dilution gas into the housing is guided to the inside of the housing, and the introduction port is further connected to the exhaust port. An exhaust device characterized by being directed to the side.